Patches reports the agentset of all patches in a model, while patch reports a specific patch. They are commonly used to command the patches to do something in an ask patches [ ... ] context. To report a specific patch, use patch x y, for example ask patch 2 -3 [set pcolor green] would set the patch with an x-coordinate of 2 and a y-coordinate of -3 to green, while ask patches [ set pcolor green ] would change all of the patches in the model to green.
Once you mastered the patches primitive, don't stop there. Check out the resources below to improve your NetLogo skills.
patches primitive:clear-patchesclears the patches by resetting all patch variables to their default initial values
patches-ownDeclare a variable that belongs to patches.